Improved cowpea for crops and livestock in West Africa

Cowpea trials have shown dual-purpose dry season varieties can withstand the harsh climate of sub-Saharan AfricaCGIAR

The dry season is a lean time in sub-Saharan Africa with food scarce for both farmers and their livestock. With one of the highest population growth rates in the world and increasing pressure on agriculture, integrating crops and livestock is an effective way to maximise land-use in this vast and populous region.

Growing cowpea (Vigna unguiculata) is a popular choice for farmers across Africa. It is widely-cultivated, with millions of smallholders dependent on it for food, feed and a source of income. The grain provides a cheap source of protein, while the haulms (leaves and stalks) are cut and stored for use as fodder. As a nitrogen-fixing legume, cowpea also helps improve soil fertility on marginal land, and cereal crops such as maize, millet and sorghum can be sown after cowpea cropping.

Until the introduction of improved varieties, different varieties of cowpea were grown for different uses; early-maturing varieties cultivated for human consumption during the relatively short growing season, with later-maturing varieties grown for fodder. After harvesting the cowpea pods, cattle graze the fields, feeding on the stover and providing a source of organic manure. But after the growing season has ended, stocks of cowpea grain and haulms diminish and prices peak at the height of the dry season - when both food and fodder are needed most.

Dual-purpose for added value

Improved varieties developed by scientists at the International Institute of Tropical Agriculture (IITA) and International Livestock Research Institute (ILRI) are able to withstand semi-arid conditions and provide both food and feed during the dry season from the same piece of land. These dual-purpose varieties are planted so that they mature after the normal growing season has finished, providing an invaluable source of food and feed during the dry season. Providing more grain and higher quality fodder, these improved varieties have already been adopted by large numbers of farmers in Nigeria.

Nigeria sows approximately four million hectares to cowpea each year, making it the world's largest producer. In Kano state, in the semi-arid north of the country, dual-purpose dry season cowpea has had a significant impact on farming communities, who usually have to brace themselves for tough times when food and fodder are in short supply.

New cowpea varieties have proven successful in Kano, NigeriaCGIAR

In many cases, cultivation of improved dual-purpose dry season cowpea varieties has replaced wheat production due to the high prices of inorganic fertiliser required, whereas cowpea only requires organic fertiliser to produce acceptable yields. Resource-poor farmers also prefer cowpea to wheat because harvesting requires less machinery and labour and the crop needs less water. The yields are also more reliable and profitable than wheat or rainy season cowpea. The accidental release of one of the improved varieties saw its rapid spread from farmer-to-farmer as its drought-tolerant benefits became apparent.

Spreading the benefits

ILRI estimates that up to 1.4 million hectares of land in West Africa could be planted with the new cowpea varieties, directly benefiting over nine million people. "It is both satisfying and at the same time challenging," says Shirley Tarawali of ILRI. "It is satisfying because it is improving livelihoods, and challenging because there is a need to work in new ways with new partners to improve agricultural systems. One of the most important things is to keep the momentum going."

Scientists are now working to resolve some of the problems associated with cowpea production and storage. The crop is particularly susceptible to nematode attacks, with researchers working on resistant varieties. Aphids also cause problems at the seedling stage, thrips and pod borers at the flowering and pod formation stages, and insects such as weevils can destroy the crop during storage. Fungal, bacterial and viral diseases are also ongoing issues. At an institutional level, there is a pressing need to improve seed multiplication and distribution systems and improve farmers' access to the improved varieties, knowledge of which has so far spread mostly by word-of-mouth.

Now and next

Cultivation of improved dual-purpose dry season cowpea has transformed farming to a year-round, rather than seasonal activity in Nigeria. The added benefits, besides increased food supply for humans and livestock and regenerated soils, has been higher incomes and higher employment through harvesting, processing and marketing of cowpea and cowpea products. But equally important is that the new technology complements the widespread adoption of mixed crop-livestock systems in the region, improving the sustainability of farming practices. Improved cowpea varieties are now likely to be introduced in East Africa, South America and Southeast Asia.